class Sum
{
public:
    Sum()
    {
        _sum += _i;
        ++_i;
    }
    static int Getsum()
    {
        return _sum;
    }
private:
    static int _i;
    static int _sum;

};

int Sum::_i = 1;
int Sum::_sum = 0;

class Solution
{


public:
    int Sum_Solution(int n)
    {
        Sum arr[n];
        return Sum::Getsum();
    }
};